1. Field of the Invention
This invention relates to compounds for modulating protein kinase enzymatic activity and the resultant modulation of cellular activities such as proliferation, differentiation, programmed cell death, migration, chemoinvasion and metabolism. Even more specifically, the invention relates to compounds which inhibit, regulate and/or modulate kinase receptor signal transduction pathways related to the changes in cellular activities as mentioned above, compositions which contain these compounds, and methods of using them to treat kinase-dependent diseases and conditions.
2. Summary of Related Art
Improvements in the specificity of agents used to treat various disease states such as cancer, metabolic, and inflammatory diseases is of considerable interest because of the therapeutic benefits which would be realized if the side effects associated with the administration of these agents could be reduced. Traditionally, dramatic improvements in the treatment of cancer are associated with identification of therapeutic agents acting through novel mechanisms.
Protein kinases are enzymes that catalyze the phosphorylation of proteins at the hydroxy groups of tyrosine, serine and threonine residues of proteins. The kinase complement of the human genome contains 518 putative protein kinase genes (Manning et al, Science, (2002), 298, 1912). The consequences of this activity include effects on cell differentiation, proliferation, transcription, translation, metabolism, cell cycle progression, apoptosis, metabolism, cytoskeletal rearrangement and movement; i.e., protein kinases mediate the majority of signal transduction in eukaryotic cells. Furthermore, abnormal protein kinase activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to cancer. Chromosomal mapping has revealed that over 200 kinases map to disease loci, including cancer, inflammatory and metabolic disease.
Tyrosine kinases can be categorized as receptor type or non-receptor type. Receptor-type tyrosine kinases have an extracellular, a transmembrane, and an intracellular portion, while non-receptor type tyrosine kinases are wholly intracellular.
Receptor-type tyrosine kinases are comprised of a large number of transmembrane receptors with diverse biological activity. In fact, about 20 different subfamilies of receptor-type tyrosine kinases have been identified. One tyrosine kinase subfamily, designated the HER subfamily, is comprised of EGFR (HER1), HER2, HER3, and HER4. Ligands of this subfamily of receptors identified so far include epithelial growth factor, TGF-alpha, amphiregulin, HB-EGF, betacellulin and heregulin. Another subfamily of these receptor-type tyrosine kinases is the insulin subfamily, which includes INS-R, IGF-IR, and IR-R. The PDGF subfamily includes the PDGF-alpha and -beta receptors, CSFIR, c-kit and FLK-II. Then there is the FLK family, which is comprised of the kinase insert domain receptor (KDR), fetal liver kinase-1 (FLK-1), fetal liver kinase-4 (FLK-4) and the fms-like tyrosine kinase-1 (Flt-1). The PDGF and FLK families are usually considered together due to the similarities of the two groups. For a detailed discussion of the receptor-type tyrosine kinases, see Plowman et al. (1994) DN&P 7(6): 334-339, which is hereby incorporated by reference.
The non-receptor type of tyrosine kinases is also comprised of numerous subfamilies, including Src, Frk, Btk, Csk, Abl, Syk/Zap70, Fes/Fps, Fak, Jak, and Ack. Each of these subfamilies is further sub-divided into varying receptors. For example, the Src subfamily is one of the largest and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr, and Yrk. The Src subfamily of enzymes has been linked to oncogenesis. For a more detailed discussion of the non-receptor type of tyrosine kinases, see Bolen (1993) Oncogene, 8:2025-2031, which is hereby incorporated by reference.
Serine-threonine kinases play critical roles in intracellular signal transduction and include multiple families, such as STE, CKI, AGC, CAMK, and CMGC. Important subfamilies include, the MAP kinases, p38, JNK and ERK, which modulate signal transduction resulting from such diverse stimuli as mitogenic, stress, proinflammatory and antiapoptotic pathways. Members of the MAP kinase subfamily have been targeted for therapeutic intervention, including p38a, JNK isozymes and Raf.
Since protein kinases and their ligands play critical roles in various cellular activities, deregulation of protein kinase enzymatic activity can lead to altered cellular properties, such as uncontrolled cell growth associated with cancer. In addition to oncological indications, altered kinase signaling is implicated in numerous other pathological diseases, such as immunological disorders, metabolic and cardiovascular diseases, inflammatory diseases, and degenerative diseases. Therefore, both receptor and non-receptor protein kinases are attractive targets for small molecule drug discovery.
One therapeutic use of kinase modulation relates to oncological indications. For example, modulation of protein kinase activity for the treatment of cancer has been demonstrated successfully with the FDA approval of Gleevec® (imatinib mesylate, produced by Novartis Pharmaceutical Corporation of East Hanover, N.J.) for the treatment of Chronic Myeloid Leukemia (CML) and gastrointestinal stroma cancers. Gleevec is a selective Abl kinase inhibitor.
Goals for development of small molecule drugs include modulation (particularly inhibition) of cell proliferation and angiogenesis, two key cellular processes needed for tumor growth and survival (Matter A. (2001) Drug Disc Technol 6, 1005-1024). Anti-angiogenic therapy represents a potentially important approach for the treatment of solid tumors and other diseases associated with dysregulated vascularization, including ischemic coronary artery disease, diabetic retinopathy, psoriasis and rheumatoid arthritis. Cell antiproliferative agents are also desirable to slow or stop the growth of tumors.
Insulin is the central hormone governing metabolism in vertebrates (reviewed in Steiner et al. (1989) in Endocrinology, DeGroot, eds. Philadelphia, Saunders: 1263-1289). In humans, insulin is secreted by the beta cells of the pancreas in response to elevated blood glucose levels, which normally occur following a meal. The immediate effect of insulin secretion is to induce the uptake of glucose by muscle, adipose tissue, and the liver. A longer-term effect of insulin is to increase the activity of enzymes that synthesize glycogen in the liver and triglycerides in adipose tissue. Insulin can exert other actions beyond these “classic” metabolic activities, including increasing potassium transport in muscle, promoting cellular differentiation of adipocytes, increasing renal retention of sodium, and promoting production of androgens by the ovary. Defects in the secretion and/or response to insulin are responsible for the disease diabetes mellitus, which is of enormous economic significance. Within the United States, diabetes mellitus is the fourth most common reason for physician visits by patients; it is the leading cause of end-stage renal disease, non-traumatic limb amputations, and blindness in individuals of working age (Warram et al. (1995) in “Joslin's Diabetes Mellitus”, Kahn and Weir, eds., Philadelphia, Lea & Febiger, pp. 201-215; Kahn et al. (1996) Annu. Rev. Med. 47:509-531; Kahn (1998) Cell 92:593-596). Beyond its role in diabetes mellitus, the phenomenon of insulin resistance has been linked to other pathogenic disorders including obesity, ovarian hyperandrogenism, and hypertension. Insulin resistance, hyperestrinism and the associated hyperandrogenism may play a role in the onset of some malignancies, such as endometrium cancer, breast cancer and prostate cancer (Guastamacchia E, et al. (2004) Curr Drug Targets Immune Endocr Metabol Disord. 4:59-66). The physiologic effects of insulin are mediated by specific association of the peptide hormone with a cell surface receptor, the insulin receptor (INRS), with concomitant activation of a signal transduction pathway in responding tissues. The INRS has been well characterized at the molecular level; it is a member of a large family of tyrosine kinase receptors (Ullrich et al. (1985) Nature 313:756-761). INRS signaling has been shown to involve a number of intracellular participants (White and Kahn (1994) J. Biol. Chem. 269:1-4; Kahn et al. (1998) Supra.). These participants include the so-called insulin receptor substrate, or IRS-1, which is phosphorylated by an activated insulin receptor kinase. IRS-1 in turn associates with phosphatidyl-inositol-3-kinase (PI3K). A number of other protein kinases and signaling proteins have been implicated in this signal transduction mechanism and presumably participate in a “kinase cascade” that leads to the modification and regulation of a host of intracellular enzymes, structural proteins, and transcription factors.
Insulin-like Growth Factor 1 Receptor (IGF1R) is an integral membrane tyrosine kinase receptor that binds insulin-like growth factor with high affinity. IGF1R plays a critical role in transformation events and human cancer (LeRoith and Helman (2004) Cancer Cell 5:201-202). It is highly over-expressed in most malignant tissues where it functions as an anti-apoptotic agent by enhancing cell survival through the PI3K pathway, and also the p53 pathway. IGF1R has been linked to various disease states, such as breast and ovarian cancer (Maor et al. (2000) Molec. Genet. Metab. 69: 130-136), metastatic uveal melanoma (All-Ericsson, C. et al. (2002) Invest. Ophthal. Vis. Sci. 43: 1-8), macular degeneration (Lambooij, A. C. et al. (2003) Invest. Ophthal. Vis. Sci. 44: 2192-2198), and intrauterine growth retardation and poor postnatal growth (Roback, E. W. et al. (1991) Am. J. Med. Genet. 38: 74-79), among others.
Microtubules have a central role in the regulation of cell shape and polarity during differentiation, chromosome partitioning at mitosis, and intracellular transport. Microtubules undergo rearrangements involving rapid transitions between stable and dynamic states during these processes. Microtubule affinity regulating kinases (MARKs) are a novel family of protein kinases that phosphorylate microtubule-associated proteins and trigger microtubule disruption (Drewes, G., et al. (1997) Cell 89: 297-308). EMK1 (MARK2) is a serine/threonine protein kinase with 2 isoforms, which differ by the presence or absence of a 162-bp alternative exon (Espinosa, L. and Navarro, E. (1998) Cytogenet. Cell Genet. 81:278-282). Both human isoforms are co-expressed in a number of cell lines and tissues, with the highest expression found in heart, brain, placenta, skeletal muscle, and pancreas, and at lower levels in lung, liver, and kidney (Inglis, J. et al. (1993) Mammalian Genome 4: 401-403). EMK1 is a regulator of polarity and also a modulator of Wnt-beta-catenin signaling, indicating a link between two important developmental pathways (Sun T et al. (2001) Nature Cell Biology 3: 628-636). Due to the physical location of this gene, 11q12-q13, EMK1 is a candidate gene for carcinogenic events (Courseaux, A. et al. (1995) Mammalian Genome 6: 311-312), and has been associated with colon and prostate cancer (Moore, T. M., et al. (2000) J Biol Chem 275:4311-22; Navarro, E., et al. (1999) Biochim Biophys Acta 1450: 254-64). Increased expression of EMK1 has been associated with increased inflammation in protocol biopsies of transplanted patients (Hueso M et al. (2004) Biochimica Et Biophysica Acta 1689: 58-65). Emk protein kinase is also essential for maintaining immune system homeostasis and its loss may contribute to autoimmune disease in mammals (Hurov J et al. (2001) Molecular and Cellular Biology 21: 3206-3219).
Cell motility is stimulated by extracellular stimuli and initiated by intracellular signaling proteins that localize to sites of cell contact with the extracellular matrix termed focal contacts. Focal adhesion kinase (FAK) is an intracellular protein-tyrosine kinase (PTK) that acts to regulate the cycle of focal contact formation and disassembly required for efficient cell movement. FAK is activated by a variety of cell surface receptors and transmits signals to a range of targets. FAKs are known to target paxillin and are substrates for Src family kinases (Calalb et al. (1995) Molec. Cell. Biol. 15: 954-963). Thus, FAK acts as an integrator of cell motility-associated signaling events. Activation of FAK may be an important early step in cell growth and intracellular signal transduction pathways triggered in response to certain neural peptides or to cell interactions with the extracellular matrix. FAK also functions in promoting cell invasion (Schlaepfer D D and Mitra S K (2004) Curr Opin Genet Dev. 14: 92-101). FAK2 is another member of the FAK subfamily of protein tyrosine kinases. The FAK2 gene encodes a cytoplasmic protein tyrosine kinase involved in calcium-induced regulation of ion channels and activation of the map kinase signaling pathway. FAK2 protein may represent an important signaling intermediate between neuropeptide-activated receptors or neurotransmitters that increase calcium flux and the downstream signals that regulate neuronal activity. FAK2 undergoes rapid tyrosine phosphorylation and activation in response to increases in the intracellular calcium concentration, nicotinic acetylcholine receptor activation, membrane depolarization, or protein kinase C activation. FAK2 binds CRK-associated substrate, nephrocystin, GTPase regulator associated with FAK, and the SH2 domain of GRB2.
Abl (Abelson murine leukemia viral oncogene homolog) is a protein tyrosine kinase involved in cellular proliferation, differentiation, adhesion and survival. Alterations of Abl by chromosomal translocation lead to malignant transformations. The t(9;22) translocation, resulting in a fusion protein Bcr-Abl with constitutive kinase activity, occurs in greater than 90% of chronic myeloid leukemia (CML), 25-30% of adult and 2-10% of childhood acute lymphoblastic leukemia (ALL), and rare cases of acute myelogenous leukemia (AML). The tyrosine kinase activity of Bcr-Abl is critical for malignant transformation. Gleevec® (Imatinib mesylate), a small-molecule inhibitor of Bcr-Abl kinase, was approved for the treatment of CML in 2001. Despite its early success, patients treated with Gleevec® have developed resistance to the therapy. Various mutations in the Abl kinase domain have been identified and are responsible for Gleevec®-resistant disease progression (Gorre M E, Mohammed M, Ellwood K, et al., Science 2001; 293:876-80). Molecular studies have demonstrated that these mutations modify the protein conformation of the kinase active site and thus interfere with the binding of Gleevec® (Shah N P, Nicoll J M, Nagar B, et al., Cancer Cell 2002; 2:117-25; Branford, S. et al., Blood 99, 3472-3475 (2002); Branford, S. et al., Blood 102, 276-283 (2003); Branford, S. et al., Blood 104, 2926-2932 (2004); Hochhaus, A. et al., Leukemia 16, 2190-2196 (2002); Roche-Lestienne, C. et al., Blood 100, 1014-1018 (2002); Roche-Lestienne, C., Lai, J. L., Darre, S., Facon, T. & Preudhomme, C., N. Engl. J. Med. 348, 2265-2266 (2003)). Second-generation Gleevec® analogs (e.g. AMN107) and other kinase inhibitors (e.g. Dasatinib) have been developed to inhibit many of the Gleevec®-resistant Abl mutants (Martinelli G, Soverini S, Rosti G, Cilloni D, Baccarani M., Haematologica 2005; 90:534-41). Both AMN107 and Dasatinib have shown improved response rates in CML patients, as compared to Gleevec®. However, neither compound can inhibit the T315I Abl mutant. It has been reported that a significant number of patients who relapsed in the treatment with Dasatinib have had or developed the T315I mutation (Shah N P, Sawyers C L, Kantarjian H M, et al., “Correlation of Clinical Response to BMS-354825 with BCR-ABL Mutation Status in Imatinib-Resistant Patients with Chronic Myeloid Leukemia (CML) and Philadelphia Chromosome-Associated Acute Lymphoblastic Leukemia (Ph+ALL)”; ASCO Annual Meeting 2005; Abstract #6521).
Accordingly, the identification of small-molecule compounds that specifically inhibit, regulate and/or modulate the signal transduction of kinases, is desirable as a means to treat or prevent disease states associated with abnormal cell proliferation and metabolism is an object of this invention. In addition, there is an unmet medical need to develop inhibitors of various forms of Abl, including the T315I mutant, for the treatment of Gleevec®-resistant CML and Bcr-Abl positive ALL.